Printhead dispensing deposition material and method of forming printed object

ABSTRACT

A building material discharge head is provided which uses a flow path structure which can be produced with extremely low-cost materials such as plates, etc., and which can discharge, in a prescribed place, a prescribed amount of a building material, even one with a high viscosity. This building material discharge head is provided with, a first heating plate which configures a first lateral wall, which is a part of the lateral wall forming the flow path through which the material flows and which heats the material inside of the path, a closing plate which configures a second lateral wall, which is the part of the lateral wall other than the first lateral wall, a discharge opening which is formed at one end of the path and communicates with the path, and a material supply opening which is formed at the other end of the path and communicates with the path.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage of International Application No.PCT/JP2015/079183, having an International Filing Date of 15 Oct. 2015,which designated the United States of America, and which InternationalApplication was published under PCT Article 21(2) as WO Publication No.2016/185626 A1, and which claims priority from and the benefit ofJapanese Application No. 2015-127059, filed on 24 Jun. 2015 and JapaneseApplication No. 2015-102185, filed on 19 May 2015, the disclosures ofwhich are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present invention relates to a printhead dispensing depositionmaterial for discharging (dispensing) a deposition material in the casewhere a three-dimensional fabricated (formed) object is manufacturedwith a 3D printer and a fabrication (forming) method forthree-dimensional fabrication. More specifically, the present inventionrelates to a printhead dispensing deposition material which can bemanufactured at low cost and assures easy control of discharging of thedeposition material and a method of forming.

BACKGROUND ART

In recent years, manufacturing a three-dimensional fabricated objectwith a 3D printer using a computer has become popular. In such 3Dprinters, a three-dimensional model is expressed as a collection ofsectional shapes. Thus, a 3D printer discharges a deposition material toa predetermined spot by three-dimensionally moving a nozzle whichdischarges a deposition material or by moving a table for the fabricatedobject in order to form a fabricated object. One example of materialsfor forming such fabricated object includes materials which are formedinto a melted state by increasing its temperature such as thermoplasticresins and metals having a low melting point. Also, a photofabricationmethod, in which a light curing resin (such as ultraviolet-curing resin)is selectively cured by lighting, and an inkjet method, in which a lightcuring resin, a thermoplastic resin, a wax, and the like are dischargedfrom an inkjet nozzle for laminate fabrication, are known. Also, areaction type curing method, in which a base resin is discharged andsubsequently a curative agent is discharged, is known. Theabove-mentioned thermally melting material is discharged to apredetermined spot by means of computer control, is solidified as thetemperature drops, and a solid body is formed. Therefore, athree-dimensional fabricated object can be obtained by moving thisdischarge nozzle relatively in a three-dimensional space to discharge adeposition material.

As a device discharging such deposition material, for example, onehaving a configuration as shown in FIG. 17 is known (see, for example,Non Patent Document 1). Specifically, in FIG. 17, a nozzle 61 is screwedinto one end side of a heater block 63, a barrel 62 is screwed onto theother end side, and a wire-shaped or stick-shaped deposition material isinserted to the barrel 62. Then, a deposition material is delivered fromthe barrel 62 at a constant rate, the deposition material is heated andmelted by the heat of the heater block 63, and the melted depositionmaterial is discharged at a fixed amount each time from a dischargeopening 61 a at a tip of the nozzle 61. The position of the dischargeopening 61 a is moved relatively in XYZ directions by means of computercontrol in such a way that it traces a desired three-dimensionaldrawing. From this, the melted deposition material is discharged tomanufacture a fabricated object in a desired three-dimensional shape.There is a heater, which is not illustrated, provided around this heaterblock 63 for heating the heater block 63 to a predetermined temperatureso that the deposition material is melted.

On the other hand, in the inkjet method which is mainly used to form atwo-dimensional image, ink drops (droplets) are discharged from aplurality of nozzles to perform image formation on a predeterminedrecording medium. In this recording head, pressure variation is causedby a piezoelectric device in a pressure chamber communicating with anozzle by an actuator so that an ink droplet is discharged from a nozzleopening. Also, a method of thermal inkjet is known, in which a heater (aheating element) is disposed at the bottom of a nozzle, local heating bythe heater causes bubbling of ink, the ink is boiled due to bubblecoalescence thereof, and then the ink is discharged (see pages 7 to 9,and 35 of Non Patent Document 2).

PRIOR ART DOCUMENT Non Patent Document

-   Non-Patent Document 1: “Digital Art of Design and Manufacturing by    3D Printer” (written by Kazuo Kadota, issued by NIKKAN KOGYO    SHIMBUN, LTD., 103 Pages)-   Non-Patent Document 2: “Ink Jet” (issued by The Imaging Society of    Japan on Sep. 10, 2008)

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

As mentioned above, in the configuration where the cylindrical nozzle 61and the barrel 62 are manufactured and fixed to the heater block 63,there is a problem with increase in material cost and manufacturingcost. In addition, one through-hole needs to be provided and a screwhole needs to be made in each heater block 63, and thus there is also aproblem that the entire body of the discharge device including theheater blocks becomes large. Furthermore, because the depositionmaterial is heated from the outside of the heater block 63 by a heater,the heating is indirect and the heat efficiency is not good.

In addition, as shown in FIG. 17, when the discharge (dispense) opening61 a is away from the heater block 63, it is likely that there arises aproblem that, before the deposition material is discharged to adesirable spot, the melted deposition material becomes solidified at thetip of the nozzle 61. Besides, once the deposition material becomessolidified, in order to raise the temperature of the tip of the nozzle61, the heater block 63 needs to be heated to an excessively hightemperature. However, when the temperature of the heater block 63 itselfbecomes higher than the melting point of the deposition material, thereis a problem that a filament, a linear or rod-shaped deposition materialintroduced to the barrel 62 side, is melted and cannot be pushed out ina fixed amount. Also, in case of some materials, including a polylacticresin (PLA), when a temperature thereof is elevated, they becomerecrystallized and carbonized under a certain condition, and once theyare solidified, there is a case where they are not brought to a meltedstate even if the temperature is elevated again. For such materials, thenozzle 61 needs to be discarded and replaced with new one. Consequently,the nozzle 61, which is high in manufacturing cost, is wasted, whichresults in a problem with further increase in cost. Also, as a startingmaterial of the deposition material, a semi-elastic, wire-shapedmaterial having a circular section of 1.75 mm diameter or 3.5 mmdiameter and being wound around a reel has been used. Therefore, thefilament wound around the reel becomes bulky, and space efficiency isreduced. Although a material is not widely different in volume from amaterial shaped in a flat tape, it requires a larger space for storage.However, there is a problem that a material shaped in a flat tape cannotbe used because it has a larger width and does not fit in the barrel 62or the nozzle 61.

Also, in the above-mentioned method employing an ink jet piezo-electricelement, a deposition material is not discharged continuously but isdischarged for each of small areas. However, this method employing thepiezo-electric element can be applied only to a deposition materialhaving a relatively low viscosity. Also, a pressure variation (a volumevariation) by the piezo-electric element is small, and a large amount ofa deposition material cannot be discharged at a time. Therefore, a largeamount of the discharged deposition material cannot be stacked up. As aresult, the method can manufacture a small fabricated (formed) object;however, it is not good at fabricating a large fabricated object. Also,in a thermal system, in which a heater is arranged, a depositionmaterial having a high viscosity such as one which is a fluid but not aliquid cannot be boiled. In other words, there is a problem that thethermal system cannot be applied to a high-viscosity depositionmaterial. Therefore, as mentioned above, a method, in which a depositionmaterial is continuously discharged from a nozzle, has been usedgenerally. A fabricated object cannot be manufactured by discharging ahigh-viscosity deposition material in an amount needed for each specificspot while relatively scanning either a nozzle or a fabrication(forming) table. As a result, there is a problem that a large fabricatedobject cannot be manufactured in a short time.

Thus, there is a problem that a high-viscosity deposition materialcannot be constantly discharged by a predetermined amount. Consequently,it takes time to manufacture a large-size fabricated object, and alarge-sized fabricated object is expected to be manufactured in a shorttime.

The present invention has been made to solve these problems and anobject thereof is to provide a printhead having an improved thermalefficiency, wherein at least a part of a flow path for a depositionmaterial is formed by a part of a heating plate so that the depositionmaterial is heated directly by the heating plate.

Other object of the present invention is to provide a printheaddispensing deposition material having a flow path structure body whichcan be manufactured easily without using a cylindrical, thread-cut, andthus expensive nozzle but with low-cost materials such as a platematerial, and a method of forming therewith.

Another object of the present invention is to solve a problem that themelted deposition material at the discharge opening becomes more viscousand is less fluidized or is solidified and thus unable to be discharged,by allowing the temperature of a flow path, in which a depositionmaterial is melted and flowed, to be higher at a discharge opening sidethan that at a deposition material supply opening side.

Another object of the present invention is to provide a printheaddispensing deposition material having a configuration which allows adischarge part to be dismantled so that a solidified deposition materialcan be removed in the case where the deposition material is one which issolidified after once being melted and is unable to be re-melted byelevating a temperature thereof.

Another object of the present invention is to provide a printheaddispensing deposition material having a discharge configuration in whicheven a high-viscosity material such as one which is a fluid but not aliquid can be discharged to a predetermined spot in a predeterminedamount and a fabricated object can be manufactured in a short time whilescanning either a discharge opening or a fabrication table.

Another object of the present invention is to provide a printheaddispensing deposition material and a method of forming of athree-dimensional fabricated object, in which discharge openings areformed in line and/or in a plurality of rows so that even a fabricatedobject comprising materials with different colors and materials withdifferent melting points or the like can be formed in the same layer bya single scan and at the same time a fabricated object of multiplelayers can be manufactured by a single scan.

Another object of the present invention is to provide a printheaddispensing deposition material and a method of forming in which, whenany of a melting deposition material, an ultraviolet-curable depositionmaterial, or a two-liquid mixing resin material of a base resin and acuring agent is used for fabrication or when those types are usedtogether for fabrication, a fabricated object can be reliablymanufactured by continuously discharging different resins at the samespot.

Means to Solve the Problem

The printhead dispensing deposition material for three-dimensionalfabrication of the present invention comprises a first heating plateconstituting a first side wall portion being a part of a side wall of aflow path for flowing a deposition material, and heating the depositionmaterial in the flow path; a closing plate or a second heating plateconstituting a second side wall portion, the second side wall portionbeing a part of the side wall of the flow path other than the first sidewall portion; a discharge opening communicating with the flow paths andformed on one tip of the flow path; and a material supply openingcommunicating with the flow path and formed on the other tip of the flowpath.

Here, the first side wall portion and the second side wall portionrespectively indicate portions of the side wall constituting the flowpaths, and do not necessarily indicate, for example, one or two sides ofa rectangular shape and mean a part of a peripheral wall, such as a partof an arch of a circular shape. The peripheral wall may be constitutedof the first side wall portion and the second side wall portion, and mayalso be composed of those portions and a third side wall portion.

In one embodiment, the printhead dispensing deposition material furtherincludes a flow path structure body, the flow path structure bodycomprising a plurality of plates having a through-hole of almost thesame shape respectively, and the plurality of plates being bondedtogether so as to form a third side wall portion with peripheral wallsof the through-holes, the third side wall portion being a part of theside wall of the flow paths other than the first side wall portion andthe second side wall portion, wherein one end side of the through-holeis closed by the first heating plate; and another end side of thethrough-hole is closed by the closing plate or the second heating plate,thereby the flow path being formed.

In another embodiment, a groove having a concave sectional shape isformed at a portion of the first heating plate, and the closing plate orthe second heating plate is provided to close an opening of the concavegroove so that the flow path are formed.

The printhead dispensing deposition material can have a configuration,wherein the closing plate is formed by a thin plate, a third heatingplate is further provided on a side opposite to the flow path based onthe thin plate, the third heating plate applying a heating effect on thedeposition material in the flow path, and the deposition material in theflow path is discharged (dispensed) by instantaneous heating of thethird heating plate.

The method of forming of a three-dimensional fabricated object of thepresent invention comprises, forming one side wall of flow path fordischarging (dispensing) deposition material with a thin plate,arranging a third heating plate on the side opposite to the flow pathbased on the thin plate, and fabricating (forming) a fabricated objectwhile discharging a deposition material of a specific flow path byapplying an instantaneous heating effect only to the specific flow pathwith the third heating plate.

Another embodiment of the method of forming of a three-dimensionalfabricated object of the present invention comprises, arranging aplurality of printheads dispensing deposition material having rows ofdischarge openings respectively, so as to be aligned with the rows ofdischarge openings in a same direction and a discharging direction ofthe discharge openings is in a direction intersecting with a fabrication(forming) table, and so as to be different in vertical heights of rowsof the discharge openings in at least two rows of the plurality of rows;and forming at least two layers of a fabricated object by a single scanin the x-y direction of the fabrication table provided below the rows ofthe printheads. Here, the expression of the direction of a dischargedirection from the discharge openings intersecting with a fabricationtable includes not only the discharge direction from the dischargeopenings perpendicular to the fabrication table (a table on which afabricated object is formed) but also ones inclined to it.

Effects of the Invention

According to the printhead of the present invention, because a part ofthe side wall of the flow path for the deposition material is formed bya part of the heating plate, the deposition material is directly heatedby the heat of the heating plate. As a result, thermal efficiency isconsiderably increased.

Also, the flow path structure body is formed by plates, a low-cost platematerial is used and, in addition, formation of the flow path structurebody is very easy; therefore, cost reduction is attained. In addition,manufacturing is very easy because the flow path is formed by thethrough-hole and the discharge opening is formed by a recess on theplate.

In addition, the third heating plate is provided on a part of a sidewall of the flow path with a thin plate interposed to apply a heatingeffect only to a specific flow path so that the deposition material canbe discharged only from the specific flow path with a simpleconfiguration.

Also, the discharge openings are provided in a plurality of rows and arearranged in different heights in the vertical direction in the pluralityof rows so that a plurality of layers can be accumulated by a singlescan. Therefore, even a large-size fabricated object can be manufacturedin a short time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a side view illustrating a printhead dispensing depositionmaterial of one embodiment of the present invention.

FIG. 1B is a plan view illustrating the printhead of FIG. 1A in a fixedstate.

FIG. 1C is a plan view of the side of the discharge openings of theprinthead of FIG. 1A.

FIG. 2 is an explanatory exploded view of FIG. 1A.

FIG. 3 is one example of a plan view illustrating one plate of the flowpath structure body of FIG. 1A.

FIG. 4A is a side view illustrating the first heating plate of FIG. 1A.

FIG. 4B is a plan view illustrating the first heating plate of FIG. 1A.

FIG. 5A is a plan view illustrating a situation where a cover substrateof the first heating plate has been removed in FIG. 1A, FIG. 6, and FIG.7A.

FIG. 5B is a view similar to FIG. 5A which shows a variation of FIG. 5A.

FIG. 5C is a view similar to FIG. 5A which shows a variation of FIG. 5A.

FIG. 5D is a view similar to FIG. 5A which shows a variation of FIG. 5A.

FIG. 5E is a view similar to FIG. 5A which shows a variation of FIG. 5A.

FIG. 6 is a perspective view illustrating a printhead dispensingdeposition material of another embodiment of the present invention.

FIG. 7A is a side view illustrating a printhead of another embodiment ofthe present invention.

FIG. 7B is a plan view showing the side of the discharge openings of theprinthead of FIG. 7A.

FIG. 8 is a plan view of one example of a plate constituting the flowpath structure body of FIG. 7A.

FIG. 9A is a plan view of one example of the first heating plate of FIG.7A.

FIG. 9B is a plan view of one example where the cover substrate of thefirst heating plate has been removed in FIG. 9.

FIG. 9C is a plan view of another example where the cover substrate ofthe first heating plate has been removed in FIG. 9.

FIG. 10A is a plan view illustrating one example of the thermal straingenerating member of the FIG. 7A.

FIG. 10B is a view similar to FIG. 10A which shows a variation of FIG.10A.

FIG. 10C is a view similar to FIG. 10A which shows a variation of FIG.10A.

FIG. 10D is a plan view illustrating one example of the third heatingplate of FIG. 7A.

FIG. 10E is a plan view illustrating another example of the thirdheating plate of FIG. 7A.

FIG. 11A is an explanatory view of the top surface side showing the sideof the deposition material supply openings (the side of the attachingplate) in another structural example of the flow path structure body ofthe printhead shown in FIG. 7A.

FIG. 11B is a plan view seen in a direction of arrow B of FIG. 11A.

FIG. 11C is a plan view seen in a direction of arrow C of FIG. 11B.

FIG. 11D is an explanatory view illustrating another example in whichtwo discharge openings are formed in one flow path.

FIG. 12A is an explanatory view of the top surface side, which issimilar to FIG. 11A, seen from the side of the attaching plate where twoflow path structure bodies are put together with a partition plate,which is not shown, interposed therebetween.

FIG. 12B is a plan view similar to FIG. 11C which shows the side of thedischarge openings of the FIG. 12A.

FIG. 13A is a view similar to FIG. 7A illustrating an example of aprinthead in which two of the printheads of FIG. 7A are bonded and thedischarge openings are formed in two rows.

FIG. 13B is a plan view seen from the side of supply openings (the sideof attaching plate) of FIG. 13A.

FIG. 13C is a plan view seen from the side of the discharge openings ofFIG. 13 A.

FIG. 14A is a view showing a variation of the structure of the part ofthe discharge opening.

FIG. 14B is a view showing another variation of FIG. 14A.

FIG. 14C is a view showing another variation of FIG. 14A.

FIG. 15 is a view showing an example of a drive circuit for controllingan insulating substrate of a heating plate to be at a predeterminedtemperature.

FIG. 16 is a circuit diagram showing one example of substratetemperature control.

FIG. 17 is an explanatory sectional view showing one example of aconventional nozzle for discharging a deposition material.

EMBODIMENT FOR CARRYING OUT THE INVENTION

Next, by referring to the figures, the printhead dispensing depositionmaterial of the present invention and the method of forming therewithare described. FIGS. 1A-1C show a side view, a plan view, and a planview, respectively of a printhead dispensing deposition material of oneembodiment of the invention, seen from the side of discharge (dispense)openings and FIG. 2 shows an exploded view thereof. The printheaddispensing deposition material of the embodiment, as shown in theexploded view of FIG. 2, comprises a first heating plate 2 constitutinga first side wall portion 121 (see FIG. 2), which is a part of a sidewall forming flow paths 12 (12 a, 12 b) (see FIG. 3) wherein depositionmaterials flow, and heating the deposition materials in the flow paths12; a closing plate 7 or a second heating plate (not shown) constitutinga second side wall portion 122 (see FIG. 2) which is a part of the sidewall other than the first side wall portion 121; discharge openings(orifices) 13 (13 a, 13 b) (see FIG. 3) communicating with the flowpaths 12 and formed at one end side (tip) of the flow paths 12; andmaterial supply openings (orifices) 14 (14 a, 14 b) (see FIG. 3)communicating with the flow paths 12 and formed at another end side ofthe flow paths 12. The entire body thereof is fixed to a supply device,which is not illustrated, by an assembly plate 9.

In an example of one embodiment, as shown in FIG. 3, a flow pathstructure body 1 is formed (see FIG. 2) in which a plurality of plates10 (10 a-10 c) having through-holes 12 a, 12 b of almost the same shapesare put together so that peripheral walls 123 of the through-holes formsa third side wall portion 123 which is a side wall of the flow paths 12other than the first side wall portion 121 and the second side wallportion 122. As shown in FIG. 2, one end side of the through-holes (theflow paths 12) is closed by a back surface of a insulating substrate 21of the first heating plate 2 and another end side of the through-holesis closed by the closing plate 7 or the second heating plate, which isnot illustrated, to form the flow paths 12.

Also, in other embodiment, as shown in FIG. 6 for example, a groove 21 ahaving a concave sectional shape is formed at a part of the firstheating plate 2 and the closing plate 7 or the second heating plate,which is not illustrated, is provided to close an opening of the concavegroove 21 a so that the flow path 12 may be formed. At the one end ofthis flow path 12 (the groove 21 a), the discharge opening 13 narrowerthan the groove 21 a is formed.

In the flow path structure body 1 in an example shown in FIG. 1, threeplates 10 a, 10 b, 10 c (or 10 when referred altogether as shown in FIG.3) are put and bonded together. As shown in FIG. 3, the flow paths 12(12 a, 12 b) are formed on each of the plates 10 as the through-holes sothat the melted deposition materials flow therein. In addition, thedischarge openings 13 (13 a, 13 b) are formed at each one end of thepaths 12 a, 12 b and connected therewith. The discharge opening 13 isformed as a recess having a depth of about a half of the thickness ofthe plate 10 without penetrating through the plate 10. This recess isformed by half etching, stamping, machining, or other methods. The shapeof this recess (the sectional shape of the discharge openings 13) is notlimited to the rectangular shape as shown in FIG. 1C and may be acircular shape or other shape. The number of these discharge openings13, or the number of the recesses, is as many as needed in accordancewith its intended use. Also, when these recesses are formed, a groove 15(see FIG. 3) of a similar recess is formed at a position in accordancewith the length of the printhead so that the plates 10 can be easilybent at a right angle. As shown in FIG. 2, the bent portion becomes anattaching portion 16 which is fixed to an attaching plate 5. 17 is ahole (a through-hole) for fixing the flow path structure body 1 to theattaching plate 5 with a screw.

The plates 10 are formed from a material excellent in heat conductivityand easy to be processed to have the through-hole 17 and the recesses.Taking this into consideration, a thin metal plate is preferable. As oneexample, the plate 10 shown in FIG. 3 is a stainless steel plate havinga thickness of about 0.6 mm, wherein a dimension A from a tip of thedischarge opening 13 to the groove 15 for folding is 13 mm, a dimensionB from the groove 15 to an end portion opposite to the discharge opening13 is 7.5 mm, and a width C is 10 mm. These dimensions are, however, oneexample and are not limited to this example. Also, it is illustratedthat the flow paths 12 (12 a, 12 b) have a width of 2 mm, the dischargeopening 13 a has a width of 0.4 mm, the discharge opening 13 b has awidth of 0.8 mm, and the through-hole 17 has a diameter of 3.2 mm. Whena stainless steel plate has the above-mentioned thickness, theabove-mentioned flow paths 12, through-hole 17, and external shapesthereof are easily formed by punching process. The external shapes areformed in various sizes depending on applications. The shape of asurrounding part of the discharge opening 13 is also formed freelydepending on applications. When the flow path structure body is formedby such plates 10, the flow paths 12 are formed by the through-holes onthe plates, and the discharge opening 13 is formed as a recess portionformed to have about a half depth of the plate 10; therefore, costs ofmaterials and processing are significantly low. In addition, because theflow paths 12 are formed by the through-holes and the openings thereofare directly closed by the first heating plate 2, the depositionmaterials are directly and efficiently heated.

Furthermore, the plate thickness is also not limited to the aboveexample, and the plates having various thicknesses can be used inaccordance with its intended use. Also, the number of the plates 10 tobe put together is not limited to three and can be increased more. Whenthe number of plates is increased, a number of discharge openingsconnecting with the same flow path 12 can be formed. A printheaddispensing deposition material which can vary its discharging amount canbe obtained. Specifically, the discharge opening 13 is formed by forminga recess communicating with the through-holes 12 on at least one of aplurality of the plates of the flow path structure body 1. It should benoted that one of the plates is illustrated in FIG. 3, and the externalshape and the flow paths 12 are common in each of the plates 10.However, the recesses to be discharge openings differ in their shapesand quantities. For example, in the plate 10 a and the plate 10 b onwhich the discharge openings 13 c, 13 d shown in FIG. 1C are formed, therecesses are formed to be symmetrical. Also, when two plates 10 are puttogether to form the discharge openings 13 in this manner, the recessesare not limited to be the same size or the same shape. A recess of 0.4mm width and a recess of 0.2 mm width may be put together, andrectangular and circular recesses may face each other.

The discharge opening 13 is formed, for example, by half etching.Specifically, the discharge opening is formed by forming a resist maskon a part where the discharge openings 13 are not formed, and thendipping in an etching solution or spray-etching for spraying an etchingsolution. Electrolytic etching can also be performed. A depth of etchingis controlled according to a time period of exposure to the etchant. Inthe case of too deep etching, the mechanical strength is reduced, andtherefore, the depth of etching is preferably about a half of thethickness of the plate 10 or less. When the plates 10 are thin and alarge discharge opening 13 cannot be formed, for example, as shown inthe discharge openings 13 c, 13 d of FIG. 1C, by forming similarrecesses at facing positions of the two plates 10 a and 10 b where therecesses face each other (as mentioned above, the positions of therecesses differ from each other in the two plates 10 a and 10 b), thedischarge openings 13 c, 13 d having a total depth of the both of therecesses are formed when the plates 10 a and 10 b are put together.Also, when these recesses are formed by stamping with a metal mold orthe like, depending on the shape of the metal mold or the like, recesseshaving a spherical shape or a cylindrical shape can be formed. Whenstamping as mentioned above is performed, formation of the recess andother processes of punching (for the external shape and the through-hole17), making grooves 15, or folding are performed simultaneously orcontinuously.

For example, three plates 10 a, 10 b, 10 c in which the through-holes(the flow paths 12) and the recesses (the discharge openings 13) areformed are put and bonded together, for example, with a heat resistantadhesive or the like. Then, at the grooves 15 (see FIG. 3), the plates10 a, 10 c on the opposite sides are folded to the opposite directionsrespectively, the plate 10 b in the middle is cut at the groove 15, andthe folded attaching portions 16 are fixed to the attaching plate 5,thereby forming the flow path structure body 1, as shown in FIG. 1A.Folding and cutting of the plates are possible without forming thisgroove 15. When the plates are being put together, the above-mentionedthrough-hole 17, a projecting part of the external shape, and the likeare used for alignment. It should be noted that when the plates 10consist of two plates, cutting is not necessary.

As shown in FIG. 1A, the first heating plate 2 is bonded to at least onesurface of the flow path structure body 1. On the one surface of theflow structure 1, the side of the first side surface and the side of thesecond side surface of the flow paths 12 a, 12 b formed by thethrough-holes (the right side surface and the left side surface of theflow path structure body 1 in FIG. 2) are open, however, the first sidewall portion 121 of these flow paths 12 a, 12 b is formed by a backsurface of an insulating substrate 21 of this first heating plate 2 toclose the one end side of the through-holes (the flow paths 12). Theinsulating substrate 21 of the first heating plate 2 is the hottest partbecause heating elements 22 (see FIG. 5A) are provided at one sidethereof, and the temperature of the deposition materials supplied in theflow paths 12 can be raised easily. Thus, a deposition material such asa filament is easily melted. Since not only the inside of the flow pathsis directly heated but also the temperature of the flow path structurebody 1 itself is raised, a surface on the opposite side (the othersurface of the flow path structure body 1) is also raised. However, whenthis flow path structure body 1 is so large that the temperature is notraised sufficiently, a second heating plate which is not illustrated maybe provided also on the side of the second side surface. Specifically,instead of the closing plate 7, the second heating plate having astructure similar to that of the first heating plate can be provided. Itis preferable that a thermal insulating member is, though it is notillustrated, provided on a cover substrate 26 on the opposite side fromthe insulating substrate 21 of this first heating plate 2. By doing so,heat of the first heating plate 2 is effectively used.

When the first heating plate 2 is bonded to this flow path structurebody 1, they may be adhered, for example, with a heat resistantadhesive, however, an adhesive which allows easy detachment ispreferable. The bonding also may be conducted by screwing and the like.By bonding detachably, disassembling and cleaning can be carried outwhen the deposition material becomes hardened in the flow path 12. As aresult, maintenance becomes easy.

On the other side of the flow path structure body 1, the closing plate 7is bonded so as to close openings of the through-holes constituting theflow paths 12 as the first heating plate 2 does. The second side wallportion 122 (see FIG. 2) is formed by this closing plate 7. It ispreferable that the closing plate is bonded in an easily disassemblablemanner to facilitate disassembling and cleaning of the flow pathstructure body 1. This closing plate 7 may be a ceramic plate as theinsulating substrate is, or may be other metal plate, a synthetic resinplate, an insulating film, or the like. When a discharge actuator, whichwill be described below, is formed, this closing plate 7 is preferably athin plate material or film. This closing plate 7 may be provided withthe second heating plate when the temperature of the flow path structurebody 1 is not raised sufficiently, as mentioned above. By doing so, theboth sides are heated, and the flow path structure body 1 can besufficiently heated even when the flow path structure body 1 is of alarge size. For this closing plate 7, a material having a low heatconductivity is preferable, however, it is preferable that a materialhaving the same thermal expansion coefficient as that of the insulatingsubstrate 21 of the first heating plate 2 or the same material as theinsulating substrate 21 is used because warping due to differencebetween the thermal expansion coefficients can be prevented.

The above-mentioned folded attaching portion 16 of the flow pathstructure body 1 is fixed to the attaching plate 5. As a result, theprinthead dispensing deposition material as shown in FIGS. 1A-1C isformed. It should be noted that the attaching plate 5 have a barrel 6attached thereto and a device supplying a filament (not shown) as adeposition material at a constant rate is attached to the barrel so thatthe deposition material is supplied at a regular interval. Theconfiguration employing a conventional barrel 62 (whose threaded portionin FIG. 17 is 6 mm in a diameter) is a configuration in which awire-shaped material having a circular section is supplied as mentionedabove, but in the present invention, a flat, tape-shaped material may besupplied in the barrel 6 because the sectional shape of the flow paths12 may be rectangular. As a result, a predetermined amount of thedeposition material is discharged (dispensed) from the dischargeopenings 13 at a constant rate. The flat, tape-shaped material can bewound around a reel without spatial waste, and that makes carrying andstorage of the material easy. Furthermore, a discontinuous dischargeconfiguration may be adopted without using the barrel 6, as shown inFIG. 7A which will be described below. In the example shown in FIG. 1B,two flow paths 12 (see FIG. 3) are formed, so two barrels 6 are formed.

Now, the first heating plate 2 is described in detail. In FIGS. 4A-4B,one example of the first heating plate 2 is illustrated in a side viewand a plan view. The first heating plate 2 has, as shown in FIGS. 4A-4Band FIGS. 5A-5E, the heating elements 22 for heating the insulatingsubstrate 21 are formed on one surface of the first insulating substrate21. At the heating elements 22, electrodes 23 for applying an electriccurrent in the longitudinal direction of the heating elements 22 areformed. In addition, a temperature measurement resistor 24 (see FIG. 5A)is formed near the heating elements 22. On the temperature measurementresistor 24, measurement terminals 25 for measuring electric resistancesat predetermined portions are formed. A cover substrate 26 is adhered ontop of them with a glass material or the like which is not illustratedand leads 27, 28 are connected with the electrodes 23 of the heatingelements 22, and the measurement terminals 25 (25 a, 25 b) of thetemperature measurement resistor 24, and leads 27, 28 are led out. Theconnections between these leads 27, 28 and the electrodes 23 or themeasurement terminals 25 are made by a high melting point solder or,when heat resistance against a temperature higher than 500° C. isrequired, by an inorganic electrically conductive adhesive or the like.Also, as will be described below, for the use as a printhead dispensingdeposition material, a control means including an actuator circuit ofthe heating elements 22 and a measurement circuit for measuring thetemperature of the insulating substrate 21 is provided. The controlmeans, by controlling the electric current through the heating elements22, controls the actuator circuit to adjust the temperature of theinsulating substrate 21 to a predetermined temperature. It should benoted that connecting parts between the leads 27, 28 and the electrodes23 or the measurement terminals 25 a, 25 b are protected by a protectingmember so that the leads 27, 28 are not bent at the connecting parts. Itshould be noted that, in FIG. 4B, for clarity of the drawing, only theouter-most ones, the measurement terminals 25 a, 25 b, of themeasurement terminals for temperature measurement are illustrated, andthe measurement terminal 25 c, 25 d branching from the measurementterminals 25 a, 25 b as shown in FIG. 5A are omitted.

This first heating plate 2 has a configuration similar to a conventionalheating head used for recording and erasing data on a card or others, inwhich the heating elements 22, and the temperature measurement resistor24 are provided on one surface of the insulating substrate 21 with aninsulating glaze layer consisting of glass or the like interposedtherebetween. However, in the present invention, as shown in FIG. 5A forexample, the heating elements 22 do not consist of linear portions(first heating elements) 22 a only but are shaped in which each one endof the two linear portions 22 a is coupled with a second heating element22 b provided so that they have components perpendicular to the linearportions 22 a (so that the two linear portions 22 a are coupled). As aresult, the heating elements 22 are shaped, for example, in a U shape, aV shape, an L shape, or the like and characterized in that a temperaturegradient is formed in the insulating substrate 21 and the heatingelement (the second heating element) 22 b of the bottom portion of the Ushape is disposed on the side of the discharge openings 13 of the flowpath structure body 1. It should be noted that herein, this U shape, asdescribed above and as shown in FIGS. 5B-5E for example, does not needto be literally shaped in the form of the letter U as long as it is in ashape having the two linear portions 22 a and the second heating element22 b coupling thereof and means to include other shapes such as a Cshape.

With the second heating element 22 b formed as shown in FIG. 5A, when anelectric current is applied to the heating elements 22, they generateheat and the insulating substrate 21 is heated, wherein the temperatureof the insulating substrate 21 is higher on the side where the secondheating elements 22 b is formed than the opposite side where a pair ofthe electrodes 23 are formed. In this case, as shown in FIG. 5A, whenthe second heating element 22 b is formed to be narrower than theheating elements (the first heating elements) 22 a, the linear portions,in width, a resistance value per unit length of the heating elements 22is larger than the heating elements 22 a. Because they are connected inseries, they have the same electric current, and the one with a largerresistance value generates more heat. Therefore, the temperature of thesubstrate can be raised more at the portion of the second heatingelements 22 b.

When the building material at a portion near the discharge openings isaway from a heater and its temperature drops, the viscosity thereof isincreased and the building material is solidified and thus clogging islikely to occur. However, in this embodiment, as shown above, when atemperature gradient is formed in the insulating substrate 21 and thetemperature is higher on the side of the discharge openings 13, thetemperature of the building material at the portion near the dischargeopenings is high and the building material can be discharged withexcellent fluidity. In other words, in a conventional heater block inwhich the temperature is constant throughout the entire body, thetemperature of the entire body of the heater block needs to be raised inorder to prevent the temperature of the heater block at the dischargeopenings side from dropping. However, when the temperature of thecentral part of the heater block becomes too high, deposition materialbegins to be decomposed or evaporated, which results in carbonization.Therefore, the heater block should not be heated to a high temperature.As mentioned above, by improving the fluidity, the deposition materialsare discharged with a small pressure even when the size of the dischargeopenings 13 is smaller.

For the insulating substrate 21, an insulating substrate having anexcellent thermal conductivity and comprising alumina or the like isused. Regarding the shape and dimension thereof, as more dischargeopenings 13 are needed in accordance with an intended fabricated(formed) object, the flow path structure body 1 becomes larger andaccordingly the first heating plate 2, and thus the insulating substrate21 also become larger. Therefore, the insulating substrate 21 having asize required for a purpose is used, and for example, in the abovementioned example of the flow path structure body 1, an aluminasubstrate having a size of about 10 mm square, and a thickness of about0.6 mm is used for two flow paths 12. It is a matter of course that aplurality of the first heating plates 2 may be provided to one flow pathstructure body 1. Its external shape is also not limited to arectangular shape and is shaped in accordance with a required shape ofthe flow path structure body 1. Thus, when twelve flow paths 12 areformed, as mentioned above, the first heating plate 2 (10 mm×60 mm) hasa size of six first heating plates 2 each being 10 mm square (three ofFIG. 9B). The external shape is also not limited to a rectangular shapeand is shaped in accordance with a required shape of the flow pathstructure body 1. This insulating substrate 21 is generally formed in asize from about 5 mm square to about 35 mm square, however the size isnot limited to this and may be a large size such as 10 mm×220 mm, and anelongated one may be formed in accordance with the number of dischargeopenings of a line head and others. In addition, a plurality of thisfirst heating plate 2 may be aligned so that the insulating substrate 21has a corresponding size to the size of the line head.

The cover substrate 26 which will be described below is formed toprotect the heating elements 22 and others formed on the insulatingsubstrate 21, at the same time, to increase a heat capacity of theinsulating substrate 21, and, moreover, to prevent warping of theinsulating substrate 21 due to the difference between the thermalexpansion coefficients. Therefore, though thermal conductivity is notrequired so much, an alumina substrate having the same thickness as theinsulating substrate 21 is used. This cover substrate 26 is not incontact with the flow path structure body 1 and therefore, it ispreferable that its thermal conductivity is low. Thus a material havingan even lower thermal conductivity can be used. However, when a thermalinsulating sheet is affixed to a surface of this cover substrate 26, thesame material (a material having the same thermal expansion coefficient)as that of the insulating substrate 21 can be used. Also, the printheaddispensing deposition material is usually configured so that its maximumoperating temperature is 150° C., 250° C., 500° C., or the like and aheating temperature is set to a temperature required for an intendedpurpose.

The heating elements 22 are optimally adjusted in its temperaturecoefficient, resistance value, and the like by suitably selecting andmixing powders of Ag, Pd, RuO₂, Pt, a metallic oxide, glass, and thelike. This mixed material is made into a paste, applied, and baked. Bythis process, the heating elements 22 are formed. A sheet resistance ofa resistive film formed by the baking can be changed by an amount ofsolid insulating powder. The resistance value and the temperaturecoefficient can be changed by a ratio of the both. Also, for a materialused as conductors (electrodes 23, 25, and coupling conductors 27 a-27d), a material in a similar paste form in which the proportion of Ag isincreased, and the proportion of Pd is decreased is used. By doing so,as in the heating elements 22, the conductors also can be formed byprinting. There is a case where due to connections of terminals, itneeds to be changed depending on a working temperature. The more Ag iscontained, the lower the resistance value may be. The temperaturecoefficient of resistance of the heating elements 22 is preferably agreater positive number, and it is especially preferable to use amaterial of 1000-3500 ppm/° C. Also, though it is not illustrated, whenan electrode is provided at a suitable position along the flowingdirection the electric current of the heating elements 22, a voltage canbe partially applied. By doing so, a temperature can vary at positions.

The temperature coefficient of resistance being a large positive numbermeans that as the temperature is elevated, a rate of increase in theresistance value becomes larger. Therefore, with the temperaturecoefficient of resistance being a positive value, when the temperatureis elevated excessively, the resistance value increases and a currentvalue drops, and an amount of heat generation due to resistance isreduced. Therefore, its temperature saturation is reached faster, andits temperature stability at a high temperature is excellent. Inaddition, overheating due to thermal runaway or the like can beprevented. It should be noted that a width of a normal portion of theheating elements 22 also can be adjusted to a predetermined temperaturein accordance with its intended use, and a plurality of the heatingelements 22 can be aligned in parallel.

Also, at the both ends of the heating elements 22, the electrodes 23comprising a good conductor such as a silver-palladium alloy with asmaller proportion of palladium or an Ag—Pt alloy are formed by printingor the like. The electrodes 23, as shown in FIGS. 4A-4B mentioned above,are configured so as to be connected to the lead 27, thereby beingconnected to a power source to turn on electricity to the heatingelements 22. This power source may be a direct current or an alternatingcurrent, and also may be a pulse voltage. When it is a pulse voltage, anapplying power can be controlled by changing its duty or pulsefrequency.

Near the heating elements 22, the temperature measurement resistor 24 isformed on a surface of the insulating substrate 21 in the same manner asin the heating elements 22. This temperature measurement resistor 24 ispreferably formed along the heating elements 22, as shown in FIG. 5A. Inthe example shown in FIG. 5A, the temperature measurement resistor 24 isformed in a U shape in which two linear portions are coupled, as theheating elements 22 are. The both ends thereof are connected to a pairof measurement terminals 25 a, 25 b. These measurement terminals 25 a,25 b are also formed of a good conductor material, as theabove-mentioned electrodes 23 are. To this temperature measurementresistor 24, not only a pair of the measurement terminals 25 a, 25 b areconnected at the both ends but also each one end of measurement leads 25e is respectively connected at positions one third of the length fromthe both ends, wherein the other ends of the measurement leads arerespectively connected to measurement terminals 25 c, 25 d. The reasonwill be described below.

The temperature measurement resistor 24 may be formed of the samematerial as the heating element 22, however, a material having anabsolute value (%) of the temperature coefficient as large as possibleis preferable. This temperature measurement resistor 24 is provided notfor generating heat but for detecting and controlling a temperature ofthe insulating substrate 21 so that the temperature of the insulatingsubstrate 21 reaches the melting temperature of the deposition material.Therefore, the temperature measurement resistor 24 is formed to be alittler shorter than the heating elements 22, with a width of 0.5 mm.Also, an applied voltage is suppressed to be low so that the temperaturemeasurement resistor 24 itself does not generate heat, and for example,about 5V is applied. Because this temperature measurement resistor 24 isprovided directly on the insulating substrate 21, the temperatures ofthe both are almost the same. As a result, by measuring a resistancevalue of the temperature measurement resistor 24, a temperature of asurface of the insulating substrate 21, and thus a temperature of thedeposition material being in close contact with a back surface of theinsulating substrate 21 are estimated. That is to say, because, ingeneral, a resistance value of a resistor material is changed when atemperature thereof is changed, the temperature can be measured bymeasuring the change of the resistance value. While a temperaturedetection means will be described below, a temperature of thetemperature measurement resistor 24 is detected by detecting a voltagechange at the both ends of this temperature measurement resistor 24.Therefore, a larger temperature coefficient of the resistor allows asmaller measurement error. It should be noted that the temperaturecoefficient can be positive or negative in this case.

The temperature measurement resistor 24 is not limited to the samematerial as the heating elements 22 and formed by printing or the likein accordance with its intended use. Specifically, when a microscopictemperature difference is required, a material having a different mixingratio of Ag and Pd or a totally different material having a largetemperature coefficient may be used. The temperature measurementterminals 25 a, 25 b are not necessarily formed at the ends of thetemperature measurement resistor 24. For example, as shown in FIGS.5A-5E, the temperature measurement resistor 24 may be formed in onepiece in a U shape, the temperature measurement terminals 25 c, 25 d maybe formed with the measurement lead 25 e branching from the middle partthereof and, in addition, the measurement terminals 25 a, 25 b to beconnected to the both ends may be formed. By doing so, local temperaturemeasurement becomes possible. Specifically, by using the measurementterminal 25 a and the measurement terminal 25 c, a temperature of abouta one third portion on the side of the measurement terminal 25 a of theU-shape temperature measurement resistor 24 is measured, and by usingthe measurement terminal 25 c and the measurement terminal 25 d formeasurement, a temperature near corners of the U shape (the part of thesecond heating element 22 b) is measured. In addition, by using themeasurement terminal 25 d and the measurement terminal 25 b formeasurement, a temperature of the remaining one third portion of thetemperature measurement resistor 24 is measured. Furthermore, bymeasuring with the measurement terminal 25 a and the measurementterminal 25 b, an average temperature of the whole insulating substrate21 is measured. The number of these measurement terminals is not limitedby the positions of about one third, and more measurement terminals maybe provided at smaller intervals or fewer measurement terminals may beprovided at larger intervals. Especially, because a temperature may varydepending on a position on the insulating substrate 21 when theinsulating substrate 21 is large, it is preferable that measuring pointsare provided at small intervals. The measuring position is preferablynear the heating elements 22.

It should be noted that a position where the temperature measurementresistor 24 is formed and a position of the measurement terminal 25 areset in accordance with designs such as the size of the insulatingsubstrate 21 (the first heating plate 2) or the degree of thetemperature gradient and the like.

The example shown in FIG. 5B is an example where the heating elements 22are formed in a channel-shape, wherein the width of the second heatingelement 22 b is narrower than the width of the linear portions of theheating elements (the first heating elements) 22 a. The purpose thereofis, as described above, to set the temperature of this portion to behigher than the temperatures of the parts of the first heating elements.As shown in FIG. 5B, it is preferable that a coupling conductor 27 a isprovided at least at a part of the corner. That is because, at thecorner, electric currents are concentrated at an internal portion wherea path is shorter and a resistance is smaller, and electric currentsthrough an outer circumferential side are reduced, and thus heatgeneration is difficult to be uniform. As shown in FIG. 5B, when thecoupling conductor (a conductor layer) 27 a is provided at least at apart of the corner, electric currents parallelly flowing through theheating elements 22 having a constant width flow uniformly throughoutthe coupling conductor 27 a. Thus, the electric currents uniformly flowthough the second heating element 22 b of the bottom portion, and alsothe electric currents uniformly flow throughout the first heatingelements 22 a, the linear portions. It should be noted that, in theexample shown in FIG. 5B, the electrodes 23 and others, and the couplingconductors 27 a are formed first by printing, and then the heatingelements 22 and others are formed thereon.

However, the locations thereof may be upside down, and, as shown in FIG.5C the heating elements 22 and others may be formed first, andsubsequently the electrodes 23 and the coupling conductor 27 b may beformed. The heating elements 22 may not be provided at the portionswhere the coupling conductors 27 a, 27 b are formed, however, theheating elements 22 may be provided there because the electric currentsflow through the portion of coupling conductor 27 a, where theresistance is smaller.

In the example shown in FIG. 5D, the portions of the linear heatingelements (the first heating elements) 22 a are cut and connected withcoupling conductors 27 c. With such configuration, heat generationhardly occurs at the portions connected by the coupling conductors 27 cbecause there is little resistance there. Thus a temperature near thesepositions drops. Therefore, when these coupling conductors 27 c areformed on the sides of the ends where the electrodes 23 are provided, atemperature of the insulating substrate 21 on the sides where thecoupling conductors 27 c are provided becomes lower than the sides wherethe coupling conductors 27 c are not provided. As a result, atemperature gradient is formed on the insulating substrate 21. In otherwords, a temperature gradient is formed on the insulating substrate 21even if the heating elements 22 are not formed into the above-mentionedU shape. It should be noted that, though it is not illustrated, when theheating elements 22 c and 22 d, which are parts of the heating elements22 divided into two or more pieces, have different widths and the widthsbecome narrower as they get farther from the electrodes 23, a largertemperature gradient can be formed on the insulating substrate 21. InFIG. 5D, the second heating element 22 b is formed, however thetemperature gradient can be formed without it. The number of portionswhere the heating elements 22 a is cut off and the coupling conductorlayer 27 c is formed is not limited to one portion and may be formed ata plurality of portions. Also, in this case as well, while the couplingconductor layer 27 c is formed, the heating element 22 a may be formedcontinuously. In addition, a coupling conductor 27 c may be formed onthe top of the heating element 22 a.

FIG. 5E is a figure showing a further example for forming a temperaturegradient on the insulating substrate 21. In this example, the heatingelements 22 are formed so that the heating element 22 has portions 22 eformed linearly along the direction of flow path 12, and the linearportions 22 e are formed into a tapered shape or in such a way thattheir width becomes gradually narrower, and therefore, a temperature ofthe insulating substrate 21 on the side of the discharge openings 13 ishigher than the side of the supply openings. Specifically, the heatingelements 22 are not constant in a width, are wider on the side of theelectrodes 23, and are narrower on the side opposite from the electrodes23. Even in this configuration, as the heating elements 22 e becomenarrower, as mentioned above, a series resistance value becomes larger,and thus more heat is generated. In other words, a substrate temperatureof the narrower side of the tapered heating element 22 e is raised.Therefore, when a temperature gradient is formed in this method, thesecond heating element 22 b is not necessary, although in the example ofFIG. 5E, the second heating element 22 b is formed. It should be notedthat the other parts are the same as each of the above-mentionedexamples, and therefore, the same figures are assigned to the sameparts, and the descriptions thereof are omitted.

As mentioned above, the number of the heating elements 22, the number oftemperature measurement resistors 24, and the number of measurementterminals for temperature measurement, and the like are not limited. Theheating elements 22 are formed by adjusting the number thereof or thewidth of each of the heating elements 22 so as to be heated to adesirable temperature in accordance with the size of the flow pathstructure body 1 and the melting point of the deposition material.

When the heating elements 22, the temperature measurement resistors 24,the electrodes 23, and the measurement terminals 25 are formed on onesurface of the insulating substrate 21 as shown above, the first heatingplate 2 and the second heating plate, which is not illustrated, areformed. On a surface side of this first heating plate 2, the coversubstrate 26 is affixed, via a glass adhesion layer, which is notillustrated. The cover substrate 26 may have a smaller thermalconductivity than the insulating substrate 21, but preferably is made ofa material having almost the same thermal expansion coefficient as thatof the insulating substrate 21 or a material which is the same as thatof the insulating substrate 21 and has the same thickness as theinsulating substrate 21. On the other hand, in the case where heat isnot sufficiently generated with this first heating plate 2, a multipleheating plate may be used, wherein the multiple heating plate is formedby facing the insulating substrates 21, on which these heating elements22 and others are formed, each other with an insulator interposedtherebetween or by putting them together facing in the same direction,with the cover substrate 26 affixed to an exposed surface thereof. Moreheat may be generated simply by putting the first heating plates 2together. When such a case is possible, it is preferable that this coversubstrate 26 has about the same thermal conductivity as the insulatingsubstrate 21.

In the examples of FIGS. 1A-1C, a third side wall portion 123, which isa side wall of the flow path, is formed by a side wall of thethrough-hole of the flow path structure body 1, and the both ends of thethrough-holes are constructed with the first side wall 121 of the firstheating plate 2 and the second side wall 122 of the closing plate 7.However, the flow paths 12 may be formed, without using the above flowpath structure body 1, by forming a groove 21 a having a concavesectional shape at a portion of the insulating substrate 21 or the coversubstrate 26 of the first heating plate 2, and closing an opening of thegroove 21 a by the closing plate 7 or the second heating plate. In thiscase, a circumference of the groove 21 a (see FIG. 6) formed on thefirst heating plate 2 becomes the first side wall portion of the flowpaths 12 and a part closed by the closing plate 7 becomes the secondside wall portion. An example thereof will be described in reference toFIG. 6.

FIG. 6 is illustrated showing the back surface of the insulatingsubstrate 21 of the above-mentioned first heating plate 2. Specifically,the groove 21 a is formed on the back surface of the insulatingsubstrate 21 so that the flow path 12 is formed and the narroweddischarge opening 13 is formed on one end side thereof. To this surface,the closing plate 7, or a thin plate 31 and a third heating plate 4which will be described below, or the second heating plate are bonded sothat the second side wall portion of the flow path 12 is formed. Also inthis configuration, the first side wall portion (the C-shaped portion)of the flow path 12 is formed by the first heating plate 2, and thus thedeposition material in the flow path 12 is heated very efficiently. Inthe example shown in FIG. 6, the groove 21 a is formed on the backsurface of the insulating substrate 21, however, a groove for a flowpath may be formed on the cover substrate 26 or a protecting plateformed instead of the cover substrate 26. Formation of a groove on sucha ceramic plate is conducted, for example, by either a process in whicha powdered ceramic material is pressure molded with a mold and thensintered, or a process in which grooving is conducted on a ceramicmaterial such as a green sheet which is in a state of being processedeasily, and subsequently sintering is conducted. Also, a sectional shapeof the groove forming the flow path 12 is not limited to a rectangularshape. The sectional shape may be, for example, a part of a circularshape.

The examples shown in FIGS. 1A-1C are examples of the printhead wherethe deposition materials are discharged continuously. In these cases, adischarge amount is determined depending on a device supplying amaterial such as a filament, which is not illustrated, at a constantrate in the barrel 6, and the desired material is discharged from thedesired discharge opening 13 to form a fabricated object.

FIGS. 7A-7B are figures showing further embodiments of the printheaddispensing deposition material of the invention. In FIG. 7A, while thefirst heating plate 2 is provided on the left side of the flow pathstructure body 1, it may be the same as in FIG. 1A. In this embodiment,the closing plate 7 is formed by the thin plate 31, and the thirdheating plate 4 which can locally heat the flow paths 12 (see FIG. 8) isprovided on the opposite side of the flow path structure body 1 with athermal strain generating member 32 interposed therebetween. Deformationof the thin plate 31 due to instantaneous heating of the third heatingplate 4 (while heating by the third heating plate 4 is for severalmilliseconds, a heating effect to the deposition material is, takingthermal conduction into consideration, for several tens milliseconds)may cause the deposition materials in the flow paths 12 to bedischarged. The thermal strain generating member 32 may not be provided.The third heating plate 4 is, as will be described below, formed so asto apply a heating effect on an individual flow path 12 even thoughthere are a plurality of the flow paths 12. When such third heatingplate 4 is provided, the deposition material can be dischargedintermittently from only an intended discharge opening even though thedeposition material is not only a melting type but also anultraviolet-curing resin of about 300-400 nm or a photo-curable resinsuch as one curable with a visible light of 400 nm or higher. Adeposition material such as a photo-curable resin which does not need tobe heated can be used as it is without heating the first heating plate2. For curing such photo-curable resin, an LED 8 is provided near thedischarge openings 13. The LED 8 may be one emitting light having awavelength which can cure the photo-curable resin.

Specifically, the method of forming of a three-dimensional fabricatedobject of the present invention is characterized in that one surface ofthe flow paths 12 for discharging the deposition materials is formed bythe thin plate 31, the third heating plate 4 is arranged on the oppositeside of the flow paths 12 from the thin plate 31, and an instantaneousheating effect is applied on a specific flow path only by the thirdheating plate 4 so that the deposition material in a specific flow path12 is discharged. This heating effect is, as will be described below,performed by locally causing a thermal expansion of the depositionmaterial in a specific flow path or a thermal expansion of the thinplate 31 along a specific flow path 12. By providing, between the thinplate 31 and the third heating plate 4, a piece 32 (see FIG. 10A) havinga different thermal expansion coefficient from the thin plate 31 or abimetal and then by causing a thermal strain due to the difference ofthe thermal expansion coefficients by heating of the third heating plate4, the thin plate 31 can be deformed.

The flow path structure body 1 and attachment thereof to the attachingplate 5, and a configuration of the first heating plate 2 are almost thesame as the configurations shown in FIGS. 1A-1C, however, in the flowpath structure body 1 shown in FIG. 7A, one example of the plate 10 isshown in FIG. 8, and six flow paths 12 are formed in parallel (whilethere are six flow paths 12 in FIG. 8, about twelve of them can beformed). Accordingly, six discharge openings 13 are formed in parallel,as shown in the plan view of the side of the discharge openings 13 inFIG. 7B. Therefore, a size C of the plate 10 itself is large, and awidth C is determined by the number of the flow paths 12 to be formed,wherein, for example, for twelve flow paths 12 (six in FIG. 8), thewidth is about 60 mm. A length A of the flow path including thedischarge opening 13 and a length B of the attaching portion 16 are thesame as in the example shown in FIG. 3, and thus detail descriptionthereof will be omitted. It should be noted that the plates 10 a, 10 bof the flow path structure body 1 are formed as two plates 10 in FIG.7A, but that is not an essential difference. There may be three platesand there may be two flow path structure bodies 1 of FIG. 1A. The flowpath structure bodies 1 may be formed by four or more plates. In thisprinthead, a barrel is not provided to the attaching plate 5 andopenings 51 (see FIG. 11A and FIG. 12A) leading to the material supplyopenings 14 are formed on the attaching plate 5.

Specifically, for example, a plurality of the flow paths 12 can beformed, as shown in FIG. 3 and FIG. 8, side by side in a directionperpendicular to an extending direction the flow paths 12. Then, each ofthe first side wall portions of the plurality of the flow paths 12 isformed by the first heating plate 2, each of the second side wallportions of the plurality of the flow paths is formed by the thin plate31, the third heating plate 4 is formed to heat only a specific flowpath 12 of the plurality of the flow paths 12, and a deposition materialis discharged from only the specific flow path 12 by instantaneousheating of the third heating plate 4.

It should be noted that the plates 10 are formed so that the size of theplates 10 is larger than the one in the example shown in FIG. 1A, andaccordingly the first heating plate 2 is also larger. Specifically, asshown in FIGS. 9A-9C, two first heating plates 2 formed in FIG. 5A andothers are formed in one insulating substrate 21. The heating elements22 and others are respectively the same as in the above-mentionedexamples, and thus descriptions thereof will be omitted. It should benoted that in FIG. 9A, the measurement terminals for temperaturemeasurement are all illustrated by 25 alone for clarity of the drawing.FIG. 9C illustrates other configuration of an example of formation ofthe heating elements 22. The heating elements 22 are formed so as toextent along the longitudinal direction of the insulating substrate 21.It should be noted that, in FIG. 9C, a third heating element 22 f havinga wide width for a high heat amount is formed on the side of thedischarge openings 13, and a fourth heating element 22 g having a narrowwidth for a low heat amount is formed on the opposite side. However, thematerial and others are the same as in the above-mentioned examples andthus the same parts are assigned with the same figure, and descriptionswill be omitted.

It should be noted that, in each of the above-mentioned examples, atemperature of the heating element having a narrower width is higherbecause the first heating element 22 a and the second heating element 22b are connected in series. However, in the example shown in FIG. 9C,each of the third heating element 22 f and the fourth heating element 22g are separately connected to a pair of the electrodes 23. Thus, byapplying a different voltage, a heating value of the third heatingelement 22 f can be made higher. Specifically, the temperature gradientis such that in the drawing, the temperature of the left end side of theinsulating substrate 21 is higher than that of the right end side in thesame manner as in the first heating plate 2 shown in FIG. 5A and others.In addition, in this example, a common terminal 23 b is formed in themiddle of the third heating element 22 f and the fourth heating element22 g so that different voltages can be applied to the each half thereof.By doing so, a heat-generating temperature can be controlled accordingto the flow paths 12 and even when melting temperatures of thedeposition materials supplied in the each flow paths are different, theeach flow paths 12 can be employed at the same time. This commonterminal 23 b also serves as a common terminal in the middle of thetemperature measurement resistor 24. The shape of the heating elements22 shown in the FIG. 9C is effective when there are a lot of the flowpaths 12 and can easily raise a temperature of the first heating plate 2on the side of the discharge openings 13.

When there are a plurality of the flow paths 12, the third heating plate4 provided on the other side of the flow path structure body 1 isconfigured so as to be capable of heating each of the flow paths 12respectively by application of a selective pulsed current by an externalsignal. When a pulsed voltage is applied to a specific flow path 12 bythe third heating plate 4, the flow path 12 is heated via the thin plate31 and the deposition material inside the flow path 12 is expanded. As aresult, the deposition material in the flow path 12 is pushed out anddischarged from the discharge opening 13 of the flow path 12. Thus, inthis example, the thermal strain generating member 32 (3) shown in FIG.7A is not necessary. In other words, the deposition materials in theflow paths 12 can be discharged by a volume increase of a depositionmaterial in the specific flow path 12 caused by a thermal expansion ofthe deposition material or the thin plate 31 due to heating of the thirdheating plate 4 or a volume change of the flow paths 12 caused by anexpansion of the thin plate 31.

In this case, when the thin plate 31 is formed of a material having alarge thermal expansion coefficient, it is expanded along the flow pathsthereof and then the deposition materials can be discharged by a changeof the thin plate 31 as in the thermal strain generating member, whichwill be described below. Also, even though the thermal expansioncoefficient of the thin plate 31 is not large, the volume of thedeposition material itself is increased when the temperature of thedeposition materials is raised. As a result, the deposition materials inthe flow paths 12 are pushed toward the discharge openings 13 anddischarged from discharge openings 13. In this case as well, when thethird heating plate 4 is heated instantly, the expansion occursinstantly, and when the heating action is cancelled, the temperaturedrops and the volume is reduced to normal. Therefore, in any method, thedeposition material is discharged instantly, and subsequently thedischarging stops. It should be noted that the deposition materials aresupplied from the side of the deposition material supply openings onlyand the deposition materials being melted in the flow paths 12 or beingin a fluid state at room temperature are kept being filled in the flowpaths 12. When this deposition material is a filament or a rod-shapedmaterial, it is supplied by a barrel. When the deposition material is aphoto-curable resin, although its viscosity can vary depending on itstype, any of the types is a fluid, and thus, with the discharge openings13 being set on the bottom side, the deposition material is filled intothe flow paths 12 by the self-weight thereof. When it does not fall bythe self-weight, it can be filled in the flow path 12 by applying apressure. Also, even when it is a resin or a metal having a low meltingpoint, it can fall by the self-weight in the same manner as in aparticulate material such as a photo-curable resin, when it is formedinto a powder.

On the other hand, as shown in FIG. 7A, the thermal strain generatingmember 3 (the piece 32 formed of a metal piece or a non-metal piece; seeFIG. 10A) may be affixed to the thin plate 31 between the thin plate 31and the third heating plate 4. This thermal strain generating member 3is formed by the piece 32 (see FIG. 10A) along each of the flow paths12, or the like, for example, with a material having a different thermalexpansion coefficient from the thin plate 31. When this piece 32 isheated, warpage deformation occurs to the thin plate 31 due to thedifference in the thermal expansion coefficient between the thin plate31 and the piece 32. In this case, a width of the piece 32 is preferablynarrower than a width of the flow path because the thin plate 31 isdeformed and pierces into the flow path 12 when the thermal expansioncoefficient of the piece 32 is larger than the thin plate 31. On thecontrary, if the thermal expansion coefficient of the piece 32 issmaller than the thin plate 31, the thin plate 31 is deformed to bepulled outward. Therefore, in this case, the width of the piece 32 isnot limited. When the thin plate 31 is deformed into the inside, thedeposition material in the flow path 12 is pushed out accordingly. Also,even if the thin plate 31 is pulled outward, because heating by thethird heating plate 4 is an instantaneous pulsed heating, the heatingstops immediately, and the deformation of the thin plate 31 is reversed.Thus, the volume inside the flow path 12 is increased temporarily andsubsequently reduced to normal, and while it is being reduced, thedeposition material in the flow path 12 is pushed and discharged fromthe discharge openings 13. Therefore, the thermal expansion coefficientsof the thin plate 31 and the piece 32 need to be different, however, itdoes not matter which is larger. A bimetal may be affixed directly tothe thermal strain generating member 3, as will be described below, eventhough there is no difference between the thermal strain generatingmember 3 and the thin plate. Detailed examples of that will be describedwith reference to FIGS. 10A-10E.

FIG. 10A, shows a configurational example in which the pieces 32 areprovided. In FIG. 10A, heaters 42 of the third heating plate 4 areillustrated by two-dot chain lines to show positions thereof. This thinplate 31 is affixed so as to cover one side of each of the plurality ofthe flow paths 12 of the flow path structure body 1 shown in theabove-mentioned FIG. 8. In other words, it is easy and preferable toform the thin plate 31 so that one thin plate 31 closes one side of allof the flow paths 12. This thin plate 31 may be, for example, a metalplate formed of an aluminum alloy sheet having a thickness of about 0.6mm, a porous ceramic which is easy to be deformed, or a heat-resistantinsulating film such as polyethylene and polytetrafluoroethylene. Thematerial is preferably heat-resistant, easy to be deformed, andexcellent in heat transferring.

For this thin plate 31, a variety of materials, such as a materialhaving a large thermal expansion coefficient and easy to be deformed ora material having a small thermal expansion coefficient and easy to bedeformed, are used in accordance with intended use thereof. Examples ofthe former materials include a copper alloy such as brass and analuminum alloy (duralumin) having a thermal expansion coefficient (acoefficient of linear expansion) of 20-30 ppm/° C. Examples of thelatter materials include metal plates such as Fe alloys (with differentratios of Fe—Ni—Cr) and stainless steel having a coefficient of linearexpansion of about 6 ppm. A non-metal plate may also be used. For thisthin plate 31, a material having any thickness of about 0.05-0.6 mm canbe used in accordance with its intended use. For example, when the thinplate 31 is formed so as to be deformable by heating along with thepieces 32 as the thermal strain generating member 3, the thin plate 31and the pieces 32 are affixed together and heated to deform the thinplate 31 by the difference of the thermal expansion coefficients of thethin plate 31 and the pieces 32, and accordingly the deposition materialin the flow paths 12 can be discharged. In this case, for the thin plate31, a material having a thermal expansion coefficient widely differentfrom that of a first piece 32 and easy to be deformed is selected. Forexample, when the above-mentioned aluminum alloy plate (coefficient oflinear expansion: 23 ppm/° C.) or copper alloy (coefficient of linearexpansion: about 20 ppm/° C.) is used for the thin plate 31, a 42 Fe—Nialloy plate (coefficient of linear expansion: 6 ppm/° C.) having athickness of about 0.1-0.2 mm can be used for the pieces 32. Here, forthe plates 10 constituting the flow path structure body 1, a ferroalloyis used. It should be noted that, for example, a bimetal, which will bedescribed below, can be affixed as the thermal strain generating member3 without employing this thermal expansion coefficient of the thin plate31. In this case, the thermal expansion coefficient of the thin plate 31is preferably small. In addition, it may also be possible that, withoutproviding the thermal strain generating member 3, the depositionmaterial in the flow paths 12 is heated and expanded or thermalexpansion is caused to the thin plate 31 itself for discharging. In thiscase, the thin plate 31 is preferably one which is easily deformedlargely, and an insulation film or the like may be used. It should benoted that while metals are raised as examples of the thin plate 31 andthe pieces 32, materials thereof are not limited to metals, and thoseother than metals, for example, ceramics used for a ceramic package forsemiconductor, a plate of inorganic compound such as a piezoelectricmaterial, quartz glass (coefficient of linear expansion: 0.5 ppm/° C.),and the like may be used.

For example, when the flow path 12 has dimensions of 1 mm (width)×1 mm(depth)×5 mm (length)=5 μl=5,000 nl, the discharge amount (determined bythe size of the discharge opening 13) is 0.3 mm×0.3 mm×0.05 mm(width)=0.0045 mm³=4.5 nl the coefficient of volumetric expansion of ABSis (6-13)×10⁻⁵ per P° C. Therefore, assuming it is 10×10⁻⁵, the volumeis expanded by 0.1% by 10° C. increase (when the temperature of 10% ofthe inside of the flow path 12 is raised by 100° C., the averagetemperature rise is 10° C.). Therefore, in the case of 5,000 nl×0.1%=5nl, it is larger than the above discharge amount, and for discharging asmall amount, just the thermal expansion of the deposition material isenough.

Also, the pieces 32 constituting the thermal strain generating member 3are formed along each of the flow paths 12, and in the example shown inFIG. 10A, those are coupled together at the root side thereof (oppositefrom the discharge openings) by a coupling portion 32 a and formed in ashape of comb tooth. Because the root side is away from the position ofthe heaters 42, its temperature is hardly raised. Therefore, there willnot be a difference between the thermal expansion coefficients of thepieces 32 and the thin plate 31. On the other hand, although it islaborious to affix the pieces 32 along each of the flow paths 12, withthe coupling portion 32 a, alignment of the pieces 32 to each of theflow paths 12 becomes very easy. Therefore, the pieces 32 can be affixedafter the coupling portion 32 a is aligned. What is illustrated in FIG.10A is that the thin plate 31 is affixed to a surface of the flow pathstructure body 1, and the pieces 32 are affixed to a surface thereof,wherein positions of the heaters 42 of the third heating plate 4 whichare provided thereupon are illustrated by two-dot chain lines.Specifically, the tip side of the pieces 32 is heated. Consequently,temperature increase by the third heating plate 4 is hardly provided onthe coupling portion 32 a.

The example shown in FIG. 10B is a drawing similar to FIG. 10A and theroot side of the pieces 32 are coupled by the coupling portion 32 a, andin addition to that, hat portions 32 b are formed on the tip side ofeach of the pieces 32. These hat portions 32 b are, without beingcoupled together, separately formed on each of the pieces 32 along theflow paths 12. When such hat portions 32 b are formed, the pieces 32 andthe thin plate 31 are more strongly adhered, and peeling is less likelyto occur even from a heat cycle. Specifically, a temperature near theheater 42 of the third heating plate 4 is raised, and a stress resultingfrom the difference between the thermal expansion coefficient isproduced. Thus, a peeling force becomes larger. However, the temperatureof the hat portions 32 b is not raised so much, and thus a stress causedby thermal strain is less likely to be applied. Consequently, the bothends of the pieces 32, where stress tends to be applied, are fixedtightly by the coupling portions 32 a and the hat portions 32 b. Thus,peeling forces to the pieces 32 are suppressed.

FIG. 10C is an example showing other embodiment of the thermal straingenerating member 3. Specifically, in this example, deformation based onthe difference between the thermal expansion coefficients of two kindsof materials is formed by the above-mentioned pieces 32 and secondpieces 33, without employing the difference between the thermalexpansion coefficients of the pieces 32 and the thin plate 31. In thiscase, a thin organic film such as an insulating film can be used becausethe thermal expansion coefficient of the thin plate 31 does not matter.In this case, deformation based on difference between thermal expansioncoefficients of the pieces 32 and the second pieces 33 occurs. Thedeformation causes the thin plate 31 to be pushed inward or pulled,thereby discharging the deposition material. In this case, there may beused separated pieces 32, without being coupled by the coupling portions32 a, and a commercially available bimetal can be used. Specifically,the thermal strain generating member 3 is formed of a bimetal formed bybonding at least two kinds of plate materials having different thermalexpansion coefficients, and the bimetal can be bonded to the thin plate31 along the flow paths 12. In this case as well, when the second pieces33 or the bimetal are affixed in such a way that the thin plate 31 ispulled outward, the bimetal are not limited by the width; however, whenthe thin plate 31 is deformed in such a way that it pierces into theflow paths 12, a width of the second pieces 33 or bimetal is preferablynarrower than a width of the flow paths 12. Also, in this case as well,the second pieces 33 are not limited to metal pieces, but may benon-metal pieces. It should be noted that the thermal strain generatingmember 3 is not just two kinds of materials having different thermalexpansion coefficients and affixed together and is not limited to twokinds of materials having different thermal expansion coefficients. Athird plate material having an intermediate thermal expansioncoefficient may be interposed between them and enables variousdeformations.

FIG. 10D is a plan view illustrating one example of the third heatingplate 4. Although its detailed drawing is not shown, this third heatingplate 4 may be formed in a configuration similar to the above-mentionedfirst heating plate 2. Specifically, the heaters 42 composed of theheating elements on an insulating substrate 41 similar to the insulatingsubstrate 21 of the first heating plate 2, and on the opposite sides ofthe heaters 42, a first conducting terminal 43 and second conductingterminals 44 are formed. These first conducting terminal 43 and secondconducting terminals 44 are formed by being applied with a materialhaving a low resistivity, as the above-mentioned electrodes 23,measurement terminals 25, and the coupling terminals 27 a-27 d are. Inthe example shown in FIG. 10D, the first conducting terminal 43 isformed as a common electrode, coupling each tip of the heaters 42provided along a plurality of the flow paths 12. And each of the secondconducting terminals 44 is derived as an individual terminal, and asignal can be applied to individual flow path 12. It should be notedthat, in FIG. 10D, 45 is a formation range of a protective film (whichis omitted in FIGS. 7A and 7B as well), which is made of glass or thelike, for covering and protecting surfaces of the heaters 42 and theconducting terminals 43, 44. The discharge amount is increased byincreasing a voltage applied to the heaters 42. The discharge amount canbe also increased when the heating elements (the heaters 42) are formedat two positions and heating is conducted at different timings.Specifically, the third heating plate 4 is, as shown in FIG. 10D, formedso that the heating elements 42 are formed on a second insulatingsubstrate 41 along each flow path 12 of the plurality of the flow paths12 and cause a heating effect in the specific flow path 12.

In the above example, a single heater 42 is formed; however, as shown inFIG. 10E, the heater (the heating element) 42 is divided into two ormore, and a voltage may be applied separately and individually to afirst heater 42 a and a second heater 42 b. Specifically, in FIG. 10E,44 a is a third conducting terminal and 44 b is a fourth conductingterminal, wherein, in this example, the fourth conducting terminal 44 bis connected to a portion where the first heater 42 a and the secondheater 42 b are connected in series. As a result, when a voltage isapplied between the first conducting terminal 43 and the thirdconducting terminal 44 a, this example becomes virtually the same as theexample shown in the above-mentioned FIG. 10D. On the other hand, when avoltage is applied between the first conducting terminal 43 and thefourth conducting terminal 44 b, only the second heater 42 b is heated.Also, when a voltage is applied between the third conducting terminal 44a and the fourth conducting terminal 44 b, only the first heater 42 a isheated. These voltage applications of the both cases can be conducted atintervals of several milliseconds to several tens milliseconds. Bysignal voltage application in a manner like this, various controls ofthe discharge amount can be conducted.

To this third heating plate 4, from the view point of microscopicdischarging of the deposition materials to a fabricated object,preferably a pulsed voltage is applied. Although the duration of thispulsed voltage application is very short, about several milliseconds,the temperature of the heaters 42 is raised instantly, its heat istransmitted to the pieces 32, and deformation occurs between the pieces32 and the thin plate 31 or between the pieces 32 and the second pieces33. The deformation of the thin plate 31 causes the deposition materialsto be discharged from the discharge openings 13. This application of apulsed voltage is performed in the same manner as in application of eachpixel signal in a normal thermal printer (for example, see JP S57-98373A), by inputting data serially to a shift register, and performing avoltage application to only necessary parts by parallel-out. Forcontrolling a heating amount, a duration of pulse application can bechanged by setting a latching circuit between this shift register and anAND circuit.

The flow paths 12 are formed in a plurality of rows as shown in theabove-mentioned FIG. 3 so that a line type printhead in which thedischarge openings 13 are arranged in parallel rows is obtained as shownin FIG. 1B. However, it is not necessarily that one discharge opening 13is for one flow path 12. Specifically, as shown in FIG. 11A showing aview seen from the attaching plate 5 introducing the depositionmaterials on the side opposite to discharge openings, FIG. 11B showing aview seen from a direction of an arrow B of FIG. 11A, and FIG. 11Cshowing a view seen from an arrow C of FIG. 11B, namely a view seen fromthe discharge openings 13 (a simplified view without its layerstructure), respectively, a small discharge opening 13 a and a largedischarge opening 13 b are formed in a single flow path 12, and aprinthead in which the large discharge openings 13 b and the smalldischarge openings 13 a are alternatingly and parallelly arranged inline is obtained. The size and shape of these discharge openings 13 arenot limited to those of this example. The discharge openings can beformed in a combination of any shapes. It should be noted that a barrelis not attached to the attaching plate 5 as mentioned before, and theopenings 51 are formed so as to communicate with the deposition materialsupply openings 14. The deposition materials can be discharged from theboth of the discharge openings 13 a, 13 b at the same time, or thedeposition materials can be discharged from one of them, while the otheris closed. The discharge openings 13 may diverge in a configuration suchthat, as shown in FIG. 11D, the same-size discharge openings 13 e, 13 fare formed at end portions of both sides of the flow path 12.

As the discharge openings 13 are formed in this manner, a pitch betweenthe discharge openings 13 is narrower, and thus more delicate andrefined fabricated object can be manufactured. It should be noted thatthese discharge openings 13 e, 13 f may be formed not in a single rowbut in two or more rows. By increasing the number of the plates 10 ofthe flow path structure body 1 to be put together, a lot of thedischarge openings 13 in more than one row can be formed from a singleflow path 12. Thus, when a plurality of the discharge openings 13 areformed to be connected to one of the flow paths 12 as described above, avariation of fabricated objects can be obtained. Also, for thisrefinement, so-called a shuttle system, in which a printhead is moved byabout a half pitch in the x-axis direction, may be adopted. The tablefor a fabricated (formed) object can be moved in the y-axis and z-axisdirections as well. By doing so, one movement in the y-axis directioncan stack two layers and possibly three or more layers as well.

FIGS. 12A-12B are examples of the printhead in which two flow pathstructure bodies 1 shown in FIG. 7A are put together via a heatconductive member or a closing plate, which is not illustrated. Theopenings of the through-holes constituting these flow paths 12 arerespectively closed by the above-mentioned first heating plate 2 andthin plate 31. As a result, a two-row line head is obtained, in whichboth the openings 51 and the discharge openings 13 a, 13 b are formedrespectively in two rows. For each of the line heads, drawings similarto FIG. 11A and FIG. 11C are shown. In this example, two flow pathstructure bodies 1 having different formation of the discharge openings13 are put together. It should be noted that the number of flow pathstructure bodies 1 to be put together is not limited to two and anynumber of the flow path structure bodies 1 may be put together. Withthese configurations, a multiple kinds of deposition materialscomprising different materials or a multiple kinds of depositionmaterials with different colors can be used. In addition, one layer of amulticolored and uneven fabricated material can be formed by a singlescan.

FIG. 13A is an example in which two printheads shown in FIG. 7A arebonded together with a heat insulation plate 71 interposed therebetweenso that the sides of the first heating plates 2 face each other. Itshould be noted that the number of the printheads to be jointed is notlimited to two. By doing so, line heads having a plurality of thedischarge openings 13 are formed in two lines as shown in a plan view ofFIG. 13C seen from the side of the discharge openings 13 a, 13 c. In theprinthead dispensing deposition material, the line heads are formed intwo rows, and, in addition, the discharge openings 13 can be differentsizes, as shown in FIG. 13C, in the printheads 13 a and the printheads13 c. Thus the discharge amount of the deposition material can bechanged freely. In addition, because the first heating plates 2 areprovided separately in two rows of the line heads, each of the lineheads can have different melting points. Thus different depositionmaterials can be melted in accordance with materials thereof. More kindsof various fabricated object can be manufactured in a short time. Ofcourse, in the two rows, the sizes of the discharge openings 13 a, 13 cmay be further changed, or the first heating plate 2 may be used with anultraviolet-curing resin, without being heated. In FIG. 13A, 8 is an LEDfor curing the ultraviolet-curing resin.

FIG. 13B is a plan view seen from the side of the attaching plate 5. Asis evident from FIG. 13B and FIG. 13C, the two rows of the line headsmay be formed so that positions of the flow paths are shifted by a halfpitch. The discharge openings 13 are also formed to be shifted by a halfpitch. When a plurality of rows of the line heads are formed and thereis a combination of rows shifted by a half pitch, lacking of thedeposition material between the pitches is prevented, and a highlyprecise fabricated object can be manufactured. With theseconfigurations, a multiple kinds of deposition materials comprisingdifferent materials or a multiple kinds of deposition materials withdifferent colors can be used. In addition, two or more layers of amulticolored and uneven fabricated material can be formed by a singlescan. In this case, too, as in the cases of the above-mentioned FIG. 11Cand FIG. 11D, the number of discharge openings 13 can be increased, andthe discharge openings 13 do not need to be aligned in a single row.Also, the discharge openings 13 do not need to be shifted by a halfpitch. It should be noted that, in FIG. 13B, 5 is an attaching plate,and 51 are openings leading to the material supply openings. Also, whenthe discharge openings 13 are formed in a plurality of rows in thismanner, positions of the discharge openings 13 in the vertical directioncan be easily changed depending on the rows. Two pairs of the printheadscan be obtained just by bonding them together to be shifted each other.By shifting, for example, by about 1 mm in the vertical direction, twoor more layers of a fabricated object can be formed by a single scan,and thus the fabricated object can be manufactured faster.

Also, when there are a lot of the flow paths 12 and a plurality of thedischarge openings 13 are formed in line as in the manner mentionedabove, even a multicolor-type fabricated object or the like can bemanufactured easily. In addition, it is also easier for a base resin anda curative agent to be discharged separately and mixed together. Asshown in FIG. 14A where a similar drawing of the printhead to FIG. 7A isshown in a schematic drawing, at a tip of the flow path structure body 1on the side of the discharge openings 13, a position shift is formed ina direction the flow paths 12 extend and a level difference “d” may beformed there. The level difference is formed by changing the lengths ofthe two plates 10 a, 10 b. This level difference may be formed bybonding the plates so that the flow path structure body 1 has two leveldifferences. Also, even though the flow path structure body 1 does nothave a level difference, two or more printheads may be used being puttogether so that there is a level difference at the discharge openingsat the tip. Specifically, the discharge openings are arranged in aplurality of rows in a direction intersecting with the fabricationtable, wherein vertical heights of the rows of the discharge openingsare different in at least two rows of the plurality of the rows, and atleast two layers of a fabricated object can be formed by a single scanin the x-y direction of the fabrication table provided below the rows ofthe discharge openings.

When the height of a discharged deposition material is about 1 mm, thelevel difference “d” is, for example, set to be about 1 mm and thefabricated object is scanned from a direction of the plate 10 a which islonger in a scan direction of the fabrication table to a direction ofthe plate 10 b which is shorter in the scan direction so that thedischarged deposition material is not be shaved by the printheads evenwhen the deposition material is discharged continuously. As a result, afinely made fabricated object can be formed. On the contrary, the leveldifference can be formed so as to shave off a top of the dischargeddeposition material. By doing so, a finely made fabricated object with aflat surface can be formed. The purpose of making such a shape is tomake the surface flat to enable the next layer to be adhered easily, andmake the material to be discharged and adhered easily when changingcharacteristics, viscosity, and the like of the material. The purpose ofmaking such a shape also allows for a certain degree of processing ofthe printed object, such as maintaining a constant thickness of theprinted object, maintaining constant intervals between dents, and thelike.

Also, instead of the level difference, as shown in FIG. 14B, two plates10 a, 10 b may be configured to be cut in an inclined direction. Thatalso prevents breaking of the deposition material discharged in asimilar manner by the printhead. It should be noted that in FIGS. 14Band 14C, only the part of the discharge opening is shown. Furthermore,in the example shown in FIG. 14C, the level difference is not formedbetween the two plates 10 a, 10 b, but about a half of a thickness ofthe one plate 10 a and the entire surface of another plate 10 b aredented. When a large amount of the deposition material is discharged, anenough room is secured for spreading of the discharged depositionmaterial. It should be noted that, in FIG. 14A, 55 is a cylindricalmember for keeping deposition materials for neighboring flow paths frommixing together. Also, the first heating plate 2, the third heatingplate 4, and others are conceptionally shown.

In addition, although it is not shown, the tip of the printhead may bescanned relative to the fabricated object while the printhead isdischarging the deposition material in a state of the tip of theprinthead being inclined to the fabricated object without facing thefabricated object at a right angle. By doing so, even when thedeposition material is discharged continuously, the same effect can beobtained as in the case where the above-mentioned level difference isformed, or the tip is cut in an inclined direction. A thick, fabricatedobject becomes easier to be obtained. In other words, by changing theshape of the tip of printhead or adjusting the setting angle inaccordance with the shape of the fabricated object, even a thick,fabricated object can be formed efficiently.

According to these embodiments, because the deposition material can besuitably discharged from a specific discharge opening 13 of a pluralityof the discharge openings 13 by the heating plate 4, for example, whilethe fabrication table is being scanned, the deposition material can bedischarged only on a particular spot on the fabricated object. Also,when a plurality of the discharge openings are formed, two or more spotsof the fabricated object can be formed at the same time. In addition,when a plurality of the discharge openings are formed, the dischargeamount can be changed by changing the size of the discharge openings.Furthermore, deposition materials of various colors can be discharged.Specifically, the deposition materials can be mixed after beingdischarged, or deposition materials comprising various colors andmaterials mixed in advance are prepared so that desired depositionmaterials are discharged on desirable spots respectively from differentdischarge openings. As a result, even a large fabricated object can bemanufactured freely in a short time.

Also, when a plurality of the printheads having a plurality of thedischarge openings formed in line are placed side by side, the number ofthe discharge openings are further increased, and fabricated objects canbe formed at a lot of positions at one time by a single scan. With thisconfiguration, when a resin comprising two liquids are used, a baseresin is discharged from the discharge openings of the first row and acuring agent is discharged from the discharge openings of the next row,thereby making it possible to perform reactive curing. In addition, whenthe discharge openings of a plurality of rows of the printheads areshifted per row in a vertical direction, first, the deposition materialis discharged by heads having lower-position discharge openings, andthen the deposition material is discharged by a row of thehigher-position discharge openings in the same scanning process so thattwo or more layers of the fabricated objects can be formed by a singlescan. Thus, even a large, fabricated object can be formed in a veryshort time.

When thermal gradient is formed so that the temperature of the firstheating plate 2 is higher on the side of the discharge openings 13 thanthe side of the supply openings side, the deposition material on theside of the discharge openings 13 remains in a state of being melted.Therefore, when a push force is applied to the deposition material dueto the deformation of the thin plate into the flow paths 12 or thethermal expansion of the deposition material, the deposition material islikely to be pushed toward the side of the discharge openings 13.

According to the method of the present invention for discharging thedeposition material by deformation of the thin plate by the thermalstrain generating member or for discharging the deposition material bytemperature increase of the deposition material in the flow paths,discharging of the deposition material can be controlledinstantaneously, and thus the deposition material can be dischargedwhile the fabrication table is being scanned; therefore, even a large,fabricated object can be manufactured very easily.

In addition, according to the method of the present invention fordischarging the deposition material in which the deposition material canbe discharged by changing the height of the discharge openings in eachof the heads of a plurality of rows in line, two or more layers of afabricated object can be formed by a single scan, and thus even a large,fabricated object can be formed in a short time. It should be noted thatthe thickness of each layer can be changed as well.

In FIG. 15, a temperature control means (a drive circuit) of theprinthead shown in FIG. 1A and others is shown. Specifically, this drivecircuit is an example of driving by a DC or AC power source 390, whereinpower source 390 is connected to the electrodes 23 (see FIG. 5A) via anadjusting part 370 for adjusting applied electric power, so that drivingpower is supplied to the heating element 22. Applied electric power isadjusted by transformer controlling voltage and its supplied time ofbattery, commercial power source, or commercial power source 390. As aresult, an AC power source also can be used as it is, and a voltagesupplied by a commercial AC power source 390 is adjusted by the electricpower adjusting part 370 so that a desirable temperature is obtained. Asa result, neither a DC power source nor a fan for cooling a power sourceis needed. However, a DC power source by a battery may be used. Inaddition, although it is not illustrated, heating may be conducted bypulse drive applying a pulse. In that case, the applied electric powercan be adjusted by changing its duty cycle besides changing its voltage.The temperature of the heating element is obtained from a resistancevalue of the temperature measurement resistor 24 obtained by measuring aconstant electric current supplied from a power source for measurement310 through a constant current circuit 350 and voltages V at the bothends of the temperature measurement resistor 24, using the temperaturemeasurement resistor 24. By using a change in the resistance value, atemperature of the temperature measurement resistor 24, namely, atemperature of the insulating substrate 21 (see FIG. 1A) is measured,and by using the temperature, an applied voltage and the like can beadjusted at the electricity adjusting part 370. In the adjusting part370, especially when a plurality of the heating elements 22 are placedside by side and heated, a temperature of each of the plurality of theheating elements 22 is made uniform. The adjusting part 370 is alsoeffective for a plurality of the heating elements 22 to have differenttemperatures. Therefore, when a plurality of the temperature measurementresistors 24 is provided, it is preferable that neighboring temperaturesthereof are measured individually, and an applied voltage and others areadjusted in each of the heating elements 22.

The principle of this temperature measurement will be described withreference to more detailed FIG. 16. A constant current circuit CCR(current controlled regulator) 350 is connected with the temperaturemeasurement resistor 24 in series at the both ends of the power sourcefor measurement 310 of, for example, a DC power source. Voltages V atthe both ends of the temperature measurement resistor 24 are measured,and the voltages are divided by a constant current with a temperaturedetection means 330 to obtain a resistance value of the temperaturemeasurement resistor 24 at that point of time. The temperature iscalculated from the resistance value and a temperature coefficient ofthe temperature measurement resistor 24 (determined by the materialthereof) which is known in advance. An electric power applied to theboth ends of the heating element 22 from the adjusting part 370 iscontrolled by the control means 360 in accordance with the detectedtemperature so that the insulating substrate 21 is kept at apredetermined temperature. For the temperature control of the heatingelement 22 by the control means 360, a voltage is applied in pulses andthen the duty cycle of the pulses may be changed, or the voltage itselfmay be changed. In the example shown in FIG. 16, the constant currentcircuit is provided. However, instead of the constant current circuit, areference resistance may be provided at a position where the temperatureis constant, and a voltage of the reference resistance is measured sothat the electric current is calculated, and the voltages at the bothends of the temperature measurement resistor 22 are measured. Also, thepower source for temperature measurement 310 is not necessarily a DCpower source. A constant current can be obtained in a pulse-like mannereven with an AC power source.

EXPLANATION OF SYMBOLS

-   1 Flow path structure body-   2 First heating plate-   3 Thermal strain generating member-   4 Third heating plate-   5 Attaching plate-   6 Barrel-   7 Closing plate-   8 LED-   9 Assembly plate-   10 Plate-   12 Flow path-   13 Discharge opening-   14 Material supply opening-   15 Groove-   16 Attaching portion-   21 Insulating substrate-   22 Heating element-   22 a Linear heating element (first heating element)-   22 b Second heating element-   23 Electrode-   24 Temperature measurement resistor-   25 a-25 d Measurement terminals-   25 e Temperature measurement lead-   26 Cover substrate-   27 Lead for heating element-   28 Temperature measurement lead-   27 a-27 d Coupling conductors-   55 Cylindrical member-   71 Heat insulation plate

What is claimed is:
 1. A printhead dispensing a deposition material forthree-dimensional fabrication comprising: a first heating plateconstituting a first side wall portion being a part of a side wall of aflow path for flowing a deposition material, and heating the depositionmaterial in the flow path; a closing plate or a second heating plateconstituting a second side wall portion, the second side wall portionbeing a part of the side wall of the flow path other than the first sidewall portion; a discharge opening communicating with the flow path andformed on one tip of the flow path; and a material supply openingcommunicating with the flow path and formed on another tip of the flowpath.
 2. The printhead dispensing a deposition material of claim 1,further comprising a flow path structure body, the flow path structurebody comprising a plurality of plates having a through-hole of almostthe same shape respectively, and the plurality of plates being bondedtogether so as to form a third side wall portion with peripheral wallsof the through-holes, the third side wall portion being a part of theside wall of the flow path other than the first side wall portion andthe second side wall portion, wherein one end side of the through-holeis closed by the first heating plate; and another end side of thethrough-hole is closed by the closing plate or the second heating plate,thereby the flow path being formed.
 3. The printhead dispensing adeposition material of claim 1, wherein a groove having a concavesectional shape is formed at a portion of the first heating plate, andthe closing plate or the second heating plate is provided to close anopening of the concave groove so that the flow path is formed.
 4. Theprinthead dispensing a deposition material of claim 1, wherein theclosing plate is formed by a thin plate, a third heating plate isfurther provided on a side opposite to the flow path based on the thinplate, the third heating plate applying a heating effect on thedeposition material in the flow path, and wherein the depositionmaterial in the flow path is discharged by instantaneous heating of thethird heating plate.
 5. The printhead dispensing a deposition materialof claim 4, wherein a plurality of the flow paths are formed side byside in a direction perpendicular to an extending direction of the flowpath, each of the first side wall portions of the plurality of the flowpaths is formed by the first heating plate, each of the second side wallportions of the plurality of the flow paths is formed by the thin plate,the third heating plate is formed to heat only a specific flow path ofthe plurality of the flow paths, and a deposition material is dischargedfrom only the specific flow path by instantaneous heating of the thirdheating plate.
 6. The printhead dispensing a deposition material ofclaim 4, further comprising a thermal strain generating member bondedbetween the thin plate and the third heating plate, wherein thedeposition material in the flow path are discharged due to deformationof the thin plate by heating of the thermal strain generating member byinstantaneous heating of the third heating plate.
 7. The printheaddispensing a deposition material of claim 6, wherein the thin plate isformed by a metal or nonmetal plate, and the thermal strain generatingmember is formed by a metal or nonmetal piece having a different thermalexpansion coefficient from the thin plate and is a piece bonded to thethin plate along the flow path.
 8. The printhead dispensing a depositionmaterial of claim 6, the thermal strain generating member is formed by abimetal made by bonding at least two kinds of plate materials havingdifferent thermal expansion coefficients, and the bimetal is bonded tothe thin plate along the flow path.
 9. The printhead dispensing adeposition material of claim of 4, wherein the deposition material inthe flow path is discharged by a volume increase of the depositionmaterial in the specific flow path caused by a thermal expansion of thedeposition material or the thin plate due to heating of the thirdheating plate or a volume change of the flow path caused by a thermalexpansion of the thin plate.
 10. The printhead dispensing a depositionmaterial of claim 5, wherein the third heating plate is formed so thatheating elements are formed on a second insulating substrate along eachflow path of the plurality of the flow paths and cause a heating effectin the specific flow path.
 11. The printhead dispensing a depositionmaterial of claim 10, wherein a heating element of the third heatingplate formed along the flow path is divided into two or more, and anelectrode terminal is formed so that a voltage can be applied to each ofthe divided heating elements individually.
 12. The printhead dispensinga deposition material of claim 1, wherein the first heating plate or thesecond heating plate comprises: a first insulating substrate, abelt-shaped heating element, the belt-shaped heating element beingformed on a surface of the first insulating substrate and heating thefirst insulating substrate, at least one pair of electrodes, the pair ofelectrodes being capable of flowing an electric current in alongitudinal direction of the heating element, a temperature measurementresistor formed on the surface of the first insulating substrate alongthe heating element near the heating element, and at least one pair ofmeasurement terminals for measuring an electric resistance at apredetermined region of the temperature measurement resistor.
 13. Theprinthead dispensing a deposition material of claim 12, wherein aheating element of the first heating plate is formed so as to be capableof heating the flow path and the neighborhood of the discharge opening,and the heating element is formed so that a temperature of the flow pathon a side of the discharge opening is higher than that on a side of thesupply opening.
 14. The printhead dispensing a deposition material ofclaim 13, wherein the heating element of the first heating plate has twolinear portions of heating elements along a direction of the flow path,each one end of the linear portions being connected with other heatingelement, and wherein a planar shape of the heating element is in aU-shape, and the heating element of the bottom portion of the U-shape isformed so as to be on the side of the discharge opening of the flow pathstructure body.
 15. The printhead dispensing a deposition material ofclaim 13, wherein the heating element is formed so as to have a portionformed linearly along the direction of the flow path, and wherein thelinear portion is formed into a tapered shape, or a width of the heatingelement becomes narrower step by step, or the heating element ispartially replaced with conductor layer along the linear portion,thereby making the temperature of the side of the discharge openinghigher than the side of the supply opening.
 16. (canceled)
 17. Theprinthead dispensing a deposition material of claim 14, wherein at leastportions of corners of the U shape are connected with conductor layers.18. The printhead dispensing a deposition material of claim 2, wherein arecess communicating with the through-holes is formed on at least one ofthe plurality of plates of the flow path structure body so that thedischarge opening is formed.
 19. The printhead dispensing a depositionmaterial of claim 1, wherein a plurality of the discharge openings areformed on one of the flow path.
 20. The printhead dispensing adeposition material of claim 2, wherein a plurality of the flow pathstructure bodies are lapped with a heat conductive member or a closingplate being disposed therebetween, and the first heating plate or thethin plate is bonded to the both outer side surfaces of the plurality ofthe flow path structure bodies.
 21. The printhead dispensing adeposition material of claim 2, wherein first and second printheadsdispensing a deposition material are bonded with a heat resistance plateinterposed so as to face to the first heating plate each other, each ofthe first and second printheads comprising the flow path structure body,the first heating plate formed on one surface side of the flow pathstructure body, and a third heating plate formed on the other surfaceside of the flow path structure body with a thin plate interposed,thereby having a plurality of rows of discharge openings so as to bealigned with discharge openings in the same direction.
 22. The printheaddispensing a deposition material of claim 21, wherein each of the flowpath structure bodies has a plurality of discharge openings in line, andwherein each row of the discharge openings of the plurality of the flowpath structure bodies is positioned in a different height in anextending direction of the flow path.
 23. (canceled)
 24. (canceled) 25.A method of forming a three-dimensional fabricated object, comprising:forming one side wall of flow path for discharging a deposition materialwith a thin plate, arranging a third heating plate on the side oppositeto the flow path based on the thin plate, and fabricating a fabricatedobject while discharging a deposition material of a specific flow pathby applying an instantaneous heating effect only to the specific flowpath with the third heating plate.
 26. The method of forming of claim25, wherein the heating effect is applied by locally causing a thermalexpansion of the deposition material in the specific flow path or athermal expansion of the thin plate along the specific flow path. 27.The method of forming of claim 25, wherein the heating effect is appliedby providing, between the thin plate and the third heating plate, apiece having a different thermal expansion coefficient from the thinplate or a bimetal, and deforming the thin plate by causing a thermalstrain due to the difference of the thermal expansion coefficientsresulting from heating of the third heating plate.
 28. The method offorming of any one of claim 25, wherein the deposition material isdischarged while heating a discharge opening side of the flow path bythe first heating plate so that a temperature thereof is higher thanthat of a supply opening side of the flow path.
 29. (canceled)
 30. Aprinthead dispensing a deposition material for three-dimensionalfabrication comprising: a flow path structure body having a flow path,wherein a discharge opening is formed on one tip of the flow path and amaterial supply opening is formed on another tip of the flow path, and aheating plate for heating the deposition material supplied into the flowpath, wherein the heating plate forms a part of a side wall forming theflow path.
 31. A printhead dispensing a deposition material forthree-dimensional fabrication comprising: a flow path structure bodyhaving a flow path, wherein a discharge opening is formed on one tip ofthe flow path and a material supply opening is formed on another tip ofthe flow path, and a heating plate for heating the deposition materialsupplied into the flow path, wherein the heating plate comprises aninsulating substrate and a heating element provided on one surface ofthe insulating substrate.
 32. The printhead dispensing a depositionmaterial of claim 31, wherein the heating plate is disposed with anothersurface of the insulating substrate facing toward the flow path.
 33. Theprinthead dispensing a deposition material of claim 31, furthercomprising another heating plate disposed on the opposite side of theflow path.